IP Range Calculator – Calculate Start & End IP
Find start IP, end IP, total addresses, and matching CIDR for any IPv4 block.
Introduction
Determine how many addresses lie between two IPv4 endpoints and get a CIDR that covers the span.
How to use this ip range calculator tool
- Enter starting IPv4 address.
- Enter ending IPv4 address.
- Click Calculate.
- Review total count and suggested CIDR.
What Is This Tool?
An IP range calculator counts addresses from a start IP through an end IP and suggests the smallest summarizing CIDR block.
Useful when logs show a span of addresses or when merging allocations.
How to Use This Tool
- Enter starting IPv4 address.
- Enter ending IPv4 address.
- Click Calculate.
- Review total count and suggested CIDR.
Formula / Calculation Logic
Total addresses = end − start + 1 (integer form).
Smallest covering CIDR is the shortest prefix whose network ≤ start and broadcast ≥ end.
Examples
Sample inputs and expected outputs:
| Input | Result |
|---|---|
| 192.168.1.1 – 192.168.1.254 | 254 addresses — fits in 192.168.1.0/24 |
| 10.0.0.0 – 10.0.0.15 | 16 addresses — /28 block |
Understanding Results
- Start IP — first address in your range.
- End IP — last address in your range.
- Total addresses — inclusive count.
- CIDR suggestion — one block that contains the entire span (may be larger than minimal gap).
Use Cases
- Firewall object sizing
- DHCP scope planning
- Log correlation
- Merger IP audits
Benefits
- Validates range order
- Suggests summarization
- Fast address counts
Common Mistakes
Avoid these errors when using this network calculator:
Planning pitfalls
- Reversed start/end
- Assuming range equals smallest subnet without checking alignment
References
Disclaimer
This calculator is for education, lab work, and network planning. Always verify production firewall, routing, and cloud VPC settings before deployment.
ip range calculator — frequently asked questions
A IP range calculator applies standard IPv4 subnet math (RFC 950 / CIDR) to compute network boundaries, masks, and host counts without manual binary conversion.
You enter IPv4 addresses, masks, or CIDR notation. The calculator bitwise-ANDs the address with the mask to find the network ID, then derives broadcast, wildcard, and host ranges.
Use it during CCNA study, VPC design, firewall rule documentation, IPAM planning, and troubleshooting when you need quick confirmation of subnet boundaries.
Yes. VSPIC runs calculations in your browser with no account required.
These calculators focus on IPv4. For IPv6 prefix planning, use our IPv6 Test and IP Subnet Calculator IPv6 tab.
CIDR writes the prefix length after a slash (e.g. /24). It replaces legacy classful networks and is used in routing tables worldwide.
A subnet mask marks which bits belong to the network portion. A /24 equals 255.255.255.0 with 254 usable hosts in typical subnets.
Yes. RFC 1918 addresses (10.x, 172.16–31.x, 192.168.x) use the same subnet mathematics as public space.
Set all host bits to 1 in the subnet — bitwise OR of network address with the inverted mask.
Variable Length Subnet Masking uses different prefix lengths within one parent network to minimize wasted addresses.
Next step for ip range calculator
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